Chastened 'Budgie Nine' back in Sydney after Sepang F1 'underwear' stunt

Several of the nine Australian men who sparked outrage after stripping off at the Malaysian Grand Prix returned home Friday, with Prime Minister Malcolm Turnbull saying they were lucky to escape without charge.

The men were celebrating Australian Daniel Ricciardo's Formula One win on Sunday when they stripped down to tight-fitting swimming briefs emblazoned with the Malaysian flag and drank beer from their shoes.

"We would like to urge all Australians travelling overseas in the future to be very aware of the cultural differences and sensitivities that exist in other nations," one of the nine, Nicolas Kelly, said after he landed at Sydney airport.

One of the men, Jack Walker, a staffer for Australian Defence Industry Minister Christopher Pyne, remained in Malaysia.

The men, all in their 20s, were arrested and brought before a court in the town on Sepang on Thursday to face potential charges of public indecency and national insult.

READ: Nine Aussies discharged with caution over Jalur Gemilang underwear

Judge Harith Sham Mohamad Yasin called their conduct "totally inappropriate", but ordered their release, citing an apology they read out in court, their youth, and the four days already spent in custody.

Photos of the men flaunting the country's national colours on "budgie smugglers" went viral in Malaysia following the race, provoking angry comments from some social media users who accused them of insulting the Southeast Asian nation.

Budgie smugglers is the colloquial term Australians use for Speedo-style swimwear.

Displays of public indecency are not tolerated by authorities in Muslim-majority Malaysia, with foreign offenders typically slapped with a fine before being deported.

READ: Men arrested for stripping down to Jalur Gemilang underwear at Sepang

Australian Prime Minister Turnbull said the men were lucky to get off so lightly.

"I think the Malaysian authorities were very lenient and I think the young Australian men were very repentant," Turnbull told Adelaide's commercial radio station FIVEaa.

"But they do need to reflect very seriously on their conduct.

"And it is just a reminder ... when you are overseas, you have to respect the laws of the country that you are visiting, just as we expect foreigners to, visitors to respect and comply with the laws of Australia when they are visiting us."